/*******************************************************************************
 * Copyright (c) 2009, 2011 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.ui.workingsets;


import org.eclipse.ui.IWorkingSet;

import java.text.Collator;
import java.util.Comparator;


/**
 * Comparator class to sort working sets, optionally keeping the default working set at the top.
 *
 * @since 3.5
 */
public class WorkingSetComparator implements Comparator<IWorkingSet> {

    private Collator fCollator = Collator.getInstance();

    /**
     * Boolean value to determine whether to keep default working set on the top while sorting.
     */
    private boolean fIsOtherWorkingSetOnTop;


    /**
     * Creates new instance of the working set comparator.
     */
    public WorkingSetComparator() {
        fIsOtherWorkingSetOnTop = false;
    }

    /**
     * Creates a new instance of working set comparator and initializes the boolean field value to
     * the given value, which determines whether or not the default working set is kept on top while
     * sorting the working sets.
     *
     * @param isOtherWorkingSetOnTop <code>true</code> if default working set is to be retained at
     *            the top, <code>false</code> otherwise
     */
    public WorkingSetComparator(boolean isOtherWorkingSetOnTop) {
        fIsOtherWorkingSetOnTop = isOtherWorkingSetOnTop;
    }

    /**
     * Returns <code>-1</code> if the first argument is the default working set, <code>1</code> if
     * the second argument is the default working set and if the boolean
     * <code>fIsOtherWorkingSetOnTop</code> is set, to keep the default working set on top while
     * sorting.
     *
     * @see Comparator#compare(Object, Object)
     */
    public int compare(IWorkingSet w1, IWorkingSet w2) {

        if (fIsOtherWorkingSetOnTop && IWorkingSetIDs.OTHERS.equals(w1.getId()))
            return -1;

        if (fIsOtherWorkingSetOnTop && IWorkingSetIDs.OTHERS.equals(w2.getId()))
            return 1;

        return fCollator.compare(w1.getLabel(), w2.getLabel());
    }
}

